Interpretive Summary: Water quality concerns associated with land application of poultry litter continues to make storage and disposal of poultry litter difficult. The objective of this study was to evaluate composted poultry litter (CPL) as a fertilizer source for bedding plants at various rates in comparison with commercially available inorganic fertilizers in regards to plant growth and nutrient leaching. Two experiments were conducted to evaluate use of composted poultry litter (CPL) as fertilizer for landscape annual bedding plants, with Petunia spp. ‘Celebrity Red’ and Verbena hybrida ‘Quartz Scarlet’ planted in raised beds to simulate an urban landscape. Use of CPL incorporated into landscape planting beds as a fertilizer source resulted in plants equal to or larger than plants grown with conventional inorganic fertilizers. Nitrate (NO3) and ammonia (NH4) levels in leachates from plots amended with CPL were comparable with plots amended with commercial inorganic fertilizers and nitrogen (N) levels were in most cases less in plots fertilized with CPL when compared to inorganic fertilizers when the same N rate was applied. Composted poultry litter may not be able to fully replace inorganic fertilizers, but it can reduce inorganic fertilizer requirements and provide an environmentally sound alternative to poultry waste disposal, as well as provide beneficial aspects for plant growth in annual bedding plants.

Technical Abstract:
Each year, over 16 million tons of poultry litter is produced in the U.S. Federal and state regulations now limit the amount of poultry litter that can be land-applied, making it difficult to store and dispose poultry litter. The objective of this study was to evaluate composted poultry litter (CPL) as a fertilizer source for bedding plants at various rates in comparison with commercially available inorganic fertilizers in regards to plant growth and nutrient leaching. Two experiments were conducted to evaluate use of CPL as fertilizer for landscape annual bedding plants. Petunia spp. ‘Celebrity Red’ and Verbena hybrida ‘Quartz Scarlet’ were planted in raised beds simulating an urban landscape. Prior to planting, 10 inorganic fertilizer or CPL treatments were incorporated into the raised beds including: Peafowl® brand garden grade fertilizer 13N-5.6P-10.9K (13-13-13) at rates of 4.9 g N/m2 and 9.8 g N/m2, Polyon® 13N-5.6P-10.9K (13-13-13) at rates of 4.9 g N/m2 and 9.8 g N/m2 and CPL at rates of 4.9 g N/m2, 9.8 g N/m2, 19.6 g N/m2, 29.4 g N/m2, 39.2 g N/m2, and 49 g N/m2. Use of CPL incorporated into landscape planting beds as a fertilizer source resulted in plants equal to or larger than plants grown with conventional inorganic fertilizers. Nitrate (NO3) and ammonia ( NH4) levels in leachates from plots amended with CPL were comparable with plots amended with commercial inorganic fertilizers and nitrogen (N) levels were in most cases less in plots fertilized with CPL when compared to inorganic fertilizers when the same N rate was applied. Composted poultry litter may not be able to fully replace inorganic fertilizers, but it can reduce inorganic fertilizer requirements and provide an environmentally sound alternative to poultry waste disposal, as well as provide beneficial aspects for plant growth in annual bedding plants.